Marik A. String practices sanctions and national security law and is a Senior Fellow at the Strauss Center for International Security and Law at the University of Texas at Austin.  He served for 16 years in senior U.S. government roles at the Department of State, Department of Defense, and U.S. Senate, including in the first and second Trump Administration as acting Legal Adviser (General Counsel) of the Department of State (2019-2021) and Senior Advisor to Secretary of State Marco Rubio.  Previously, he served as acting Assistant Secretary for Political-Military Affairs (2018-2019) and as Deputy Chief Counsel and Senior Professional Staff Member on the US Senate Committee on Foreign Relations (2006-2013).  He is an officer in the US Navy Reserve with domestic and overseas tours supporting European Command, the Joint Chiefs of Staff, and electronic warfare squadron VAQ-209.

He was educated at Georgetown University (J.D., Global Law Scholar), where he was an editor of The Georgetown Law Journal; the University of Vienna (M.A., Fulbright Scholar); and the University of Notre Dame (B.A.).